Fix behaviour of with_any_role with no args

User.with_any_role with no args should return all User instances having at least one role.
fix #363

lib/rolify/adapters/active_record/role_adapter.rb

@@ -51,7 +51,7 @@ def scope(relation, conditions)
           query = relation.all
         end
         query = query.joins(:roles)
-        query = where(query, conditions)
+        query = where(query, conditions) if conditions
         query
       end
 

lib/rolify/finders.rb

@@ -19,6 +19,7 @@ def with_all_roles(*args)
     end
 
     def with_any_role(*args)
+      return self.adapter.scope(self, nil) if args.empty?
       users = []
       parse_args(args, users) do |users_to_add|
         users += users_to_add

spec/rolify/shared_examples/shared_examples_for_finders.rb

@@ -116,6 +116,7 @@
     describe ".with_any_role" do
       it { should respond_to(:with_any_role) }
 
+      it { subject.with_any_role().should eq(subject.joins(:roles).all)}
       it { subject.with_any_role("admin".send(param_method), :staff).should eq([ root ]) }
       it { subject.with_any_role("admin".send(param_method), :staff, { :name => "moderator".send(param_method), :resource => Group }).should eq([ root ]) }
       it { subject.with_any_role("admin".send(param_method), "moderator".send(param_method)).should eq([ root ]) }